Depending upon the business rules and behaviors of the application you are testing, you might break your equvalence classes of cities into size-based categories or location-based categories such as these:

Population of city: under 1 million, 1 million - 2.99 million, 3 million - 8.99 million, Above 9 million

and/or

Location of city: Asia, Americas, Europe, Africa or Australia

If you reduced your list of city-related Values from 500 to 4, you would have far, far fewer pairwise tests generated when you click on the Create Tests button.

For more information:

Don't forget to explore Hexawise's Value Expansion feature here. Whenever you reduce the number of Values in Hexawise for a Parameter, you should consider using the Value Expansions feature.